xcode-cocos2D隨機數組無法調用

cocos2D隨機數組無法調用

創建了一個數組，其中包括紅黃綠（321）三個顏色，根據用戶點擊隨機選擇一個數字，然後在屏幕上顯示對應的顏色，然後系統選擇最後輸入的顏色，但是我寫的代碼沒有實現這樣的功能：

-(void)CreateEnemy:(ccTime)dt{
CCSprite *Enemy;
int a;
if (colorArray != nil) {
    a = arc4random()% [colorArray count];
}
int y = [[colorArray objectAtIndex:a] integerValue];
if (y == 1) {
    Enemy = [CCSprite spriteWithFile:@"GreenBall.png"];
    int x = arc4random()%320;
    Enemy.position = ccp(x, 530);
    id action = [CCMoveTo actionWithDuration:3 position:ccp(x, -30)];
    [Enemy runAction:[CCSequence actions:action, [CCCallFuncN actionWithTarget:self selector:@selector(spriteMoveFinished:)], nil]];
    [enemyArray addObject:Enemy];
    [self addChild:Enemy z:2 tag:1];
    NSLog(@"Green Enemy Attack!!");
}
else if (y == 2) {
    Enemy = [CCSprite spriteWithFile:@"YellowBall.png"];
    int x = arc4random()%320;
    Enemy.position = ccp(x, 530);
    id action = [CCMoveTo actionWithDuration:3 position:ccp(x, -30)];
    [Enemy runAction:[CCSequence actions:action, [CCCallFuncN actionWithTarget:self selector:@selector(spriteMoveFinished:)], nil]];
    [enemyArray addObject:Enemy];
    [self addChild:Enemy z:2 tag:1];
    NSLog(@"Yellow Enemy Attack!!");
}
else if (y == 3) {
    Enemy = [CCSprite spriteWithFile:@"RedBall.png"];
    int x = arc4random()%320;
    Enemy.position = ccp(x, 530);
    id action = [CCMoveTo actionWithDuration:3 position:ccp(x, -30)];
    [Enemy runAction:[CCSequence actions:action, [CCCallFuncN actionWithTarget:self selector:@selector(spriteMoveFinished:)], nil]];
    [enemyArray addObject:Enemy];
    [self addChild:Enemy z:2 tag:1];
    NSLog(@"Red Enemy Attack!!");
}
}

其中Y是一個隨機選擇數。

最佳回答：

在這段代碼中

if (colorArray != nil) {
   a = arc4random()% [colorArray count];
}
int y = [[colorArray objectAtIndex:a] integerValue];

[colorArray count]很有可能沒有你需要的值, 因此arc4random只能返回0 (或一組有限的值).

如果你在計算a的值之前加上一個 NSLog跟蹤, 就可以估計[colorArray count]的值了.